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United States Patent 3,525,897 ELECTRON DISCHARGE DEVICE Ernest T. DuPre, Tell City, Ind., assignor to General Electric Company, acorporation of New York Original application Aug. 31, 1964, Ser. No.393,304, now Patent No. 3,375,343, dated Mar. 26, 1968. Divided and thisapplication Oct. 11, 1967, Ser. No. 683,057

Int. Cl. H01j 5/00 US. Cl. 313-317 11 Claims ABSTRACT OF THE DISCLOSUREAn electron discharge device having an insulating stem carrying parallelstem-leads of predetermined length welded to transverse planar surfaceswithin the device. The planar surfaces may comprise the electrodes ofthe device or interconnecting plates which are in turn welded torespective portions of the electrodes transverse to the plates.

This application is a division of my copending application, Ser. No.393,304, filed Aug. 31, 1964, entitled Electron Discharge DeviceAssembly Method, now US. Pat. No. 3,375,343 issued Mar. 26, 1968, and isassigned to the assignee thereof; and this invention relates to animproved electron discharge device assembly and to the method ofmanufacturing an electron discharge device to provide the improvedassembly.

Present-day electron discharge devices ordinarily include a cagestructure comprising an assembly of the electrodes of the device and astem of insulating material 1ncluding a plurality of conducting leadssecured therein n mutually insulated fashion. A glass or metal envelope1s provided which encloses the cage structure and is hermetically sealedto the stem member to provide an evacuated or gas-filled chamber for thecage structure. The conducting leads, hereinafter referred to asstem-leads, are electrically interconnected through the stem to acorresponding plurality of terminal pins which provide for mounting thedevice in a standard tube socket, the other end of stem leads, referredto as the inner ends, also being joined, as by welding, to appropriateconnector surfaces of the electrodes to enable electrical connectionthereto and to provide mechanical support of the cage structure withmthe envelope.

One of the most costly and most time-consuming operations in themanufacture of an electron discharge device comprises the joining orwelding of the stem-leads to the electrode connector surfaces. Inaccordance with prior art techniques, each of the stem-leads of the stemmust be formed, as by bending, to establish an effective positioningthereof adjacent the electrode connector surface to which it is to bejoined, Ordinarily, this stem-lead forming can be, and is, accomplishedin automated fashion by a machine including a number of dies designed,both in their own shapes, and in their manner of actuation, forachieving the desired forming of the leads. However, the differentstem-lead forms required by different tube types necessitates arelatively large, expensive inventory of different dies and actuatingmechanisms for the machine for the different tube types. Further, whenchanging the type of tube being manufactured, a considerable expense,both from the standpoint of down-time and the actual man-hours involved,is involved in the changing of these dies and of their actuatingmechanisms for properly forming the stem leads to accommodate thedifferent configuration of the electrode connector surfaces.

Following the stem-lead forming operations, as taught by the prior art,the stem-leads are welded to the respectively associated'electrodeconnector surfaces by resistance welding. The resistance welding isperformed man- 3,525,897 Patented Aug. 25, 1970 ually by an operator Whopositions the stem and the cage structure such that they are properlyaligned, one with the other, and such that the corresponding stemdeadsare adjacent the respectively associated connector surfaces of theelectrodes. Next, while maintaining this relationship, the operatorpositions a selected one of the stem-leads and the corresponding one ofthe electrode connector surfaces intermediate two welding electrodeswhich are then actuated to bring the selected stem-lead andcorresponding connector surface into close mechanical engagement. Whilemaintaining the engagement, current is passed between the electrodes andthrough the stem-lead and connector surface to provide a resistance Weldtherebet-ween. The operator then causes the welding electrodes to beretracted, and manipulates'the cage and electrode to perform,sequentially, a resistance weld between each one of the stem-leads andthe corresponding one of the connector surfaces of the electrodes.

Despite the prior forming of the stem-leads, the intricacy of the designof the cage structure invariably requires that the operator,additionally, manually form the stem-leads to enable appropriateinterconnection thereof with the respectively associated connectorsurfaces. The intricacy of this resistance welding operation may readilybe appreciated by considering the number of welds, i.e., about a dozen,required to be performed in an electron discharge device of theminiature variety which may contain within a single envelope, despiteits small size, two or more independent electron discharge systems, suchas the well-known double triode and double pentode vacuum tubes.

In accordance with standard mass production techniques, a plantordinarily will engage in the manufacture of as many as a hundred typesof electron discharge devices during a period of a month. During thisperiod, an individual operator will be called upon to perform theresistance welding operations of positioning respectively associatedstem-leads and connector surfaces intermediate Welding electrodes onmany tube types. As each type will have a modified stem-leadconfiguration to accommodate the changed configuration, the operatormust develop a new manner of manipulating the stem and cage structure toachieve the proper and most efficient handling positions thereof inperforming the resistance welds. During such a changeover period in theproduction schedule, an individual operators production rate ordinarilydrops by as much as 50%. This, of course, must be avoided if at allpossible since the construction of electron discharge devices requiresthe utmost in efficiency and maximum work output from each operator inthe production line if the maximum ibenefit to the consumer and to themanufacturer is to be realized.

The prior art has attempted to overcome this problem of stem-leadforming by employing metallic straps which are individually welded toeach of the stem-leads and, in turn, welded to the electrode connectorsurfaces. Although avoiding the stem-forming operation, the use of thestraps has proven to be significantly more expensive than the stem-leadforming technique since the straps are an added manipulation problemand, in fact, requires that the operator in the assembly line performtwice as many resistance welds as heretofore. Further, the very basicproblem of the operators drop in output when changing production to adifferent type of electron discharge device is still present.

The present invention teaches a technique of tube manufacture offeringgreatly reduced costs, both in assembly equipment, and in operators timeon a production line. The invention comprises both a new method ofmanufacture for manufacturing electron discharge devices and a new andnovel structure which is at least electrically and mechanically equal tothose of the prior art and'of greatly reduced cost. The method ofoperation taught by the invention and the resulting structure avoid therequirement that an assembly operator become accustomed to anyparticular tube type. In particular, the stem-forming operation can betotally avoided, if desired, and the assembly operator can perform theidentical assembly steps in an identical manner regardless of the typeof device being manufactured. In addition toavoiding the intricatemanipulating of the stern and cage structure as required by prior artassembly techniques, the welding operation itself, in accordance withthe invention, is much faster, providing a plurality of welds in asingle step whereas prior art techniques required the performance of aplurality of welds in a number of Successive welding steps.

Thus, in addition to achieving higher production rates whilemanufacturing a particular device, the output level of each assemblyoperator will be maintained substantially invariant upon changes in thetype of devices being manufactured, and, in fact, in most instances theoperator need not even be aware of such a change.

Therefore, it is an object of this invention to provide an improvedmethod for the assembly of electron discharge devices.

Another object of this invention is to provide an improved method forthe assembly of stem and cage structures in an electron dischargedevice.

A further object of this invention is to provide an improved method forthe assembly of stem and cage structures of an electron discharge devicewhich eliminates the necessity of stem-lead forming.

Still another object of this invention is to provide an improved methodeliminating the necessity for stemlead forming and employing percussivewelding techniques in the manufacture of electron discharge devices.

It is still another object of this invention to provide an improvedmethod which avoids the necessity of a production line operator becomingacclimated or accustomed to the configuration of a particular type ofelectron discharge device to assemble the device quickly andefficiently.

Still a further object of this invention is to provide an improvedmethod for use in the assembly of the stem and cage structures of anelectron discharge device providing higher production levels and reducedcost.

Yet another object of this invention is to provide an improved methodfor the assembly of electrode cage and stem structures of an electrondischarge device wherein an operators output level remains unalteredupon a change in the production schedule.

It is still a further object of this invention to provide an assemblyfor an electron discharge device of improved electrical and mechanicalquantity but of greater economical benefit.

It is yet another object of this invention to provide an electrondischarge device having an electrode cage and stem assembly of greatereconomic benefit and simplified construction but of high qualityelectrical and mechanical characteristics.

It is yet a further object of this invention to provide an electrondischarge device having an electrode cage and stem assembly joined by apercussive welding operation.

It is yet another object of this invention to provide an electrondischarge device which can be assembled without the necessity ofstem-lead forming.

Other objects and advantages of this invention will be apparent to thoseskilled in the art and will be made clear as the following descriptionproceeds.

In accordance with one preferred embodiment of the invention, theimproved assembly is to be employed with a standard electrode cageproviding a plurality of electrode connector surfaces which are to besecured to a corresponding plurality of stem-leads supported by andformed integrally with a stem at the inner ends thereof. The stemcomprises a planar insulating member, generally of circularconfiguration, and the stem-leads are supported thereon in a generallycircular array and extend therefrom in mutually parallel fashion. Aninterconnecting plate of conducting material is formed to provide aplurality of interconnecting bands extending from an associated one ofthe electrode connector surfaces to a position on the periphery of theinterconecting plate, the positions about the periphery correspondingtoselected inner ends of the array of stem-leads.

In assembling the device, the interconnecting plate may be received byan appropriate support member in the apparatus depicting the inventionand the stem, with the stern leads thereof cut to equal lengths, may bereceived by a second support member. The stem is positioned such thatthe stem-leads are displaced from, but axially aligned with, acorresponding one of the interconnecting bands. An. electrical potentialdifference is established between the plurality of stem-leads and theinterconnecting plate and these elements are then brought into forgingengagement, providing a percussive weld between each of the stem-leadsand its respectively associated interconnecting band. Subsequently, orif desired, previously, the interconnecting plate is joined to theelectrode connector surfaces by a substantially identical percussivewelding technique; alternatively, a resistance weld may be effectedbetween a lip member provided on the terminal end of eachinterconnecting band and the associated electrode connector surface.

The invention may readily be understood by reference to the followingdrawings, in which:

FIG. 1 is a perspective view of apparatus useful in carrying out one ofthe steps of the assembly operation,

FIG. 2 is a perspective view of apparatus useful in carrying out anotherone of the steps of the assembly operation,

FIG. 3 is a detailed, exploded view of a modified portion of theapparatus of FIGS. 1 and 2,

FIG. 4 is a perspective view of an electron discharge device formed inaccordance with the method of the invention,

FIG. 5 is a perspective view of a partial assembly in accordance with analternative embodiment of the invention,

FIG. 6 is a perspective view of the structure of FIG. 5 showing thecompleted assembly of a cage electrode structure and a stem inaccordance with the alternative embodiment of the invention shown inFIG. 5, and

FIG. 7 is a perspective view of a further alternativ embodiment of theinvention.

In FIG. 1, the apparatus of the invention is shown to include a basemember 1 having vertical, parallel guide arms 2 and 3 joined at the topby a cross bar 4, cross bar 4 being fixedly secured thereto, as bywelding. An upper support bar 5 is fixedly secured to bearings 6 and 7to enable reciprocating vertical motion of the upper support bar 5 alongthe guide arms 2 and 3. A shaft 8 is fixedly secured to the uppersupport bar 5 and slidingly received within an aperture 9 in the crossbar 4, collar 10 being fixedly mounted to the shaft 8 by a set screw 11and abutting the top surface of cross bar 4 to limit the downward motionof the upper support bar 5. Shaft 8 includes an external thread portion12 receiving an internally threaded knurled knob 13, which engages astop 14 of spring latch 15. As the upper support bar 5 is raised, theknurled knob 13 rides against an inclined portion 14a of stop 14,deflecting spring member 15a of the spring latch 15 until knurled knob13 is raised thereabove. Upon releasing the upper support bar 5, knurledknob 13 rests upon a horizontal portion 14b of stop 14, and maintainsthe upper support bar 5 in the elevated position. Knurled knob 13 may beadjusted on the threaded portion 12 of shaft 8 to adjust the height ofthe upper support bar in its elevated position, and, similarly, collar10 may be adjusted in its position on shaft 8 by set screw 11 toregulate the distance the upper support bar 5 descends upon disengagingthe spring latch from the knurled knob 13.

A stem holder 16 is mounted on the upper support bar 5 and is providedwith a plurality of apertures 17 for receiving pins 18 of a standardstem, the stem being indicated generally by the numeral 19. The stem 19may be maintained within stem holder 16 by frictional engagement of thepins 18 thereof within the apertures 17. For convenience in insertingthe stem 19 into the stern holder 16, the latter is provided withapertures 20 which enable stem holder 16 to be removed from, andsubsequently slidingly received upon studs 21, the latter being securedto the upper support bar 5.

An insulating block 22 is mounted fixedly on the upper support bar 5 andhas secured to the surface thereof a plurality of welding currentconductor assemblies 23. Each of the welding assemblies 23 includes aflexible pinengaging element 24 formed of a resilient electricallyconducting material, such as copper. The pin-engaging ele ments 24include angular portions 25 such that, upon sliding stem holder 16 alongstuds 21 to the position shown, the angular portions 25 resilientlyengage a corresponding one of the pins 18 and provide electrical contacttherewith. Only four welding assemblies 23 have been shown for purposesof clarification in illustration, although the actual number thereof isnot limited. In the actual device, a number of welding assemblies 23will be employed to the extent necessary for providing electricalconnections to each of the pins 18.

A lower support bar 26 is fixedly secured to bearings 27 and 28 toenable reciprocating vertical motion of the lower support bar 26 alongthe guide arms 2 and 3. The lower support bar 26 is resilientlymaintained at a predetermined position by coil springs 29 and 30, thelatter being suspended from pins 31 and 32, respectively, secured tocross bar 4 and engaging pins 33 and 34, re spectively, secured to thelower support bar 26. A support unit 35 is secured to the lower support'bar 26 for resilient reciprocating motion therewith. The support unit35 includes a support bed 36 on which an interconnecting plate 37 isreceived.

Interconnecting plate 37 includes a plurality of interconnecting bands,four of which are shown as the elements 38 to 41, and a peripheralportion generally indicated by the numeral 42. The peripheral portion 42is provided with apertures 43 and 44 which coact with studs 45 and 45ato properly locate the plate 37 on bed 36.

Clamps 46 and 47 are mounted on shafts 48 and 49, respectively, forpivotal motion. The shafts 48 and 49 are received at one extremity in asuitable bearing member provided at the rear of bed 36 and pass throughfront bearing member 50. Actuating arms 51 and 52 are secured to theshafts 48 and 49, respectively, by set screws 53 and 5 4. A coil spring55 engages the pins 56 and 57 on the actuating arms 51 and 52,respectively, for imparting forces thereto respectively directed incounterclockwise and clockwise fashion, thereby effecting the desiredbiasing of clamps 36 and 47 to the positions indicated.

Clamp 46 is shown in cut-away fashion to facilitate the illustration ofthe manner in which its clamp face portion 50 extends over and bearsagainst the peripheral portion 42 of the interconnecting plate 37 forsecuring the latter in the position shown. Clamp 47 contains a similarclamp face portion 59 which, similarly to the portion 58 of clamp 46,secures the interconnecting plate 37 to the support bed 36.

In operation, the upper support bar 5 is raised, knurled knob 13 hearingagainst the surface 14a of stop 14 and deflecting spring latch 15.Knurled knob 13 then rests upon the upper surface 14b of the inclinedstop 14 to maintain the upper support bar 5 and its associatedstructures at an elevated position. As noted earlier, knurled knob 13may be adjusted in its position along the threaded portion 12 of shaft 8to vary the elevation of the upper support bar 5 when retained by thespring latch 15; the

selection of this adjustment is determined in accordance with the sizeof stem 19 employed for the type of device being manufactured and, inparticular, will vary depending on the length of the stem-leads 60 whichare supported in parallel, axial relation by the insulating base portion61 of the stem 19. Although some of the stemleads 60 are broken away, ina portion thereof, to facilitate the illustration of the apparatus, theremaining ones clearly demonstrate the parallel relation in which thestem-leads 60 extend from the insulating base 61 and also the fact thatthey are of equal length.

For positioning an interconnecting plate 37 on the support bed 36, theoperator grasps the lip portions 51a and 52b of the actuating arms 51and 52, respectively, and squeezes them together. The clamps 46 and 47are thereby rotated in a direction opposite to their normal direction ofresilient bias, raising their respective clamp face portions 58 and 59from the clamping position indicated in FIG. 1. While maintaining theclamps 46 and 47 in this open or receiving position, an interconnectingplate 37 is slid onto the support bed 36 and oriented on locating studs45 and 45a whereafter the actuating arms 51 and 52 are released andcaused to return to their engaging, or clamping, position by the coilspring 55. A thumb slot 62 is provided in the front bearing member 50 tofacilitate the insertion and removal of the interconnecting plate 37.

The percussive welding operation which the apparatus of the invention isintended to perform is indicated in FIG. 1 as already having beenaccomplished. Illustrating the apparatus in this manner facilitatesshowing the align ment of the interconnecting bands, such as 38 to 41,of the interconnecting plate 37 with selected, corresponding ones of thestem-leads 60. It is apparent, however, that the stem 19 and theinterconnecting plate 37, when initially positioned Within the sternholder 16 and on the support bed 36, respectively, will be verticallydisplaced one from the other. It is equally clear, however, that theguide members 2 and 3 accurately define the vertical motion of the uppersupport bar 5 such that the alignment of the interconnecting bands, suchas 38 to 41, along the axes of the corresponding, selected stemleads 60,is maintained at all times.

To perform the percussive welding operation, an electrical potentialdifference is established between the stemleads 60 and theinterconnecting plate 37. For this purpose, suitable electricalpotential is applied individually, to the plurality of weldingassemblies 23, in any suitable manner; likewise, a suitable electricalpotential is applied to the support unit 35. In practice, it is foundpreferable to maintain the support unit 35 at ground potential; further,it is preferable that the stem holder 16 be formed of an insulatingmaterial, whereby the entire apparatus with the exception of theelectrode welding assemblies 23 and their flexible pin-engaging elements24,'is maintained at ground potential. An advantage of using a pluralityof individual welding assemblies 23, is that different levels ofoperating potentials may be applied to selected ones of the pins 18 andtheir respective, electrically interconnected stem-leads 60. This latterarrangement may be particularly desirable and even necessary whereeither selected ones of the stem-leads 60 or their associatedinterconnecting bands such as 38 to 41, or both, are formed of differentsizes or types of metal, requiring different welding potentials.

To perform the percussive weld, after the electrical potentialdifference has been established between the stemleads 60 and theinterconnecting plate 37, the spring latch 15 is deflected in adirection toward the rear of the apparatus, thereby releasing knurledknob 13 from the stop 14. The upper support bar 5 falls, by force ofgravity, causing the stem-leads 60 to be driven against the respectivelyassociated ones of the interconnecting bands 38 to 41. The equal lengthof the stem-leads 60 causes a plurality of spark gaps to be createdbetween the inner ends thereof and each of the respectively associatedinterconnecting bands 38 to 41. These arcs create an intense localizedheating, both of the region of each of the interconnecting bands 38 to41 toward which the associated stem-leads 60 is approaching, and also ofthe terminal ends of each of the selected stem-leads 60.

The acceleration of the upper support bar as it falls, due to the forceof gravity, brings the terminal ends of the stem-leads into sharp impactwith their associated interconnecting bands 38 to 41 in a forgoingengagement, providing a percussive weld therebetween. The magnitude ofthe impact and electrical potential difference between the stem-leads 60and the interconnecting bands 38 to 41 is determined in accordance withknown percussive welding techniques and depends upon the charartericticsof the material of which the stem-leads 60 and the interconnecting plate37 are formed. To insure the production of good percussive welds, it ispreferable to cut the inner ends of stem-leads 60 at a small angle withrespect to their axes.

Springs 29 and 30 are selected to provide sufficient resilency in thepositioning of the lower support bar 26 such that, upon the impact ofthe stem-leads 60 on the interconnecting plate 37, the lower support bar26 will descend slightly to remove undue strain from the stemleads 60,thereby preventing their buckling or bending.

Following the percussive welding or joining of the stem 19 and theinterconnecting plate 37, these assembled elements may be transferred toa second machine such as that shown in FIG. 2 for percussive welding ofthe interconnecting plate 37 to a cage structure 63. The apparatus ofFIG. 2 is essentially identical to that of FIG. 1, with the exception ofthe structure carried by its support bar 26', and identical numerals areemployed for indicating the corresponding portions. The upper and lowersupport bars 5 and 26 of FIG. 2 are displaced a greater distance apartthan the upper and lower supporting bars 5 and 26 of FIG. l'toaccommodate the additional height of the cage structure 63 in FIG. 2.

Cage 63 includes upper and lower insulating spacers or micas 64 and 65between which are secured electrode structures 66 and 67. Although thecage structure 63 may comprise any type of electron discharge device,the one shown in FIG. 2 is of the double triode variety, each of theelectrode structures 66 and 67 consituting an operating electrondischarge device.

The cage structure 63 is received on a supporting base 68, the latterbeing secured to a laterally extending arm 69 of the lower support bar26'. The supporting base 68 is formed on the surfacce thereof to receivea particular cage structure 63 and includes an aligning stud 70 and,preferably, a second such stud (not shown) which passes through suitableapertures provided in the lower mica 65 to align the case structure 63on the supporting base 68 in proper relation to the assembled structurecomprising the stem 19 and the interconnecting plate 37. Cover plates 70and 71 are provided on the supporting base 68, cover plate 70 beingbroken away to indicate current conducting welding assemblies 72 and 73.

A portion of the anode 74 of the electrode structure 66 is broken awayto indicate the internal elements, namely grid support rods 75 having awire wound grid thereabout, and a cathode 76. The electrodes 74 to 76provide connector surfaces 74a to 76a extending through the lower mica65.

In the usual case, the cage structure 63 will have an identical array ofelectrode connector surfaces 74a to 76a extending through and beyondboth the upper and lower micas 64 and 65 and likewise, the electrodestructure 67 will have an identical array of electrode connectorsurfaces whereby the cage structure 63 is completely symmetrical through180" about either a vertical or a horizontal axis. In some instances,such symmetry will not exist in the cage structure 63 and the lower mica65 may be formed to provide both a keying and a guide in the positioningthereof on the supporting base 68.

Welding assemblies 72 and 73 engage the lower connector surfaces 74a and75a, respectively, of the anode 74 and the grid support rod 75 toprovide electrical contact thereto. The number of such weldingassemblies 72 and 73 and the configuration and orientation thereof is,of course, designed in accordance with the particular electrodestructures supported within the cage structure 63.

In operation, the upper support bar 5 is raised and retained in anelevated position by the engagement of knurled knob 13 on the stop 14 ofthe spring latch 15. The cage structure 63 is positioned on thesupporting base 68 in the manner indicated. Next, the stem holder 16,with the previously welded assembly of stem 19 and interconnecting plate37 inserted therein, is received on the studs 21. Appropriate weldingpotentials are applied to the welding assemblies 23 and communicatedthrough the resilient pin-engaging elements 24 thereof to the pins 18and thence through the stem-leads 60 to the associated ones of theinterconnecting bands 38 to 41. Further, the welding assemblies 72 and73 complete an electrical circuit through the anode 74 and the gridsupport rod 75 to establish an electric potential between ground at theconnector surface 74a and 75a.

Spring latch 15 is then deflected, releasing the knurled knob 13 andenabling upper support rod 5 to drop, as hereinbefore described.Electric arcs are established between the interconnecting bands 38 to 41and the electrode connector surfaces 74a and 75a of electrode structure67 and 74a and 75a of electrode structure 66, respectively.

As hereinbefore described, the electric arcs create an intense heatingbetween the associated elements which, upon impact, undergo a forgingengagement and provide a percussive weld therebetween.

The cathode connector surfaces 76a of both the electrode structures 66and 67 are shown to include conducting leads 78 secured thereto as ifperformed in a prior manufacturing step; if desired, however, suitableinterconnecting bands may be provided therefor in the interconnectingplate 37 to enable percussive welding thereto in the same manner as withthe electrode connector surfaces 74a and 76a of the anodes 74 and grids76, or these connections may be accomplished by a subsequentmanufacturing step.

Following the double percussive welding steps, the peripheral portions42 of the interconnecting plate 37 may be removed, as by breaking alongsuitably delineated rupture seams to finish the assembly, however, it isgenerally preferable to break off the peripheral portion prior to thesecond percussive welding step.

In accordance with this invention, the peripheral portions 42 may beremoved in any manner, for example, trimming with shears, or in acutting die or any other convenient means. However, breaking alongrupture seams is preferred and is the subject of the invention disclosedand claimed in application Ser. No. 393,259, now US. Pat. No.3,270,391Linehan, issued Sept. 6, 1966'. filed concurrently herewith andassigned to the same assignee.

In the very simple, and very quickly steps indicated to be performed bythe apparatus of FIGS. 1 and 2, secure electrical interconnection hasbeen achieved between selected ones of the stem-leads 60' and associatedinterconnecting bands 38 to 41 of the interconnecting plate 37 and,therethrough, to an associated electrode connector surface. Thus,electrical communication has been established between selected externalpins 18 of the insulating base 61 of stem 19 and a desired one of thenumerous electrodes within the cage structure 63. It will be appreciatedthat the forming of welds between the cage structure and theinterconnecting plate could be performed first, and in certain cases maybe preferred.

In FIG. 3 there is shown an alternative form of stem holder constitutingan improvement over the frictional engagement performed by stem holder16 of FIGS. 1 and 2 and permitting the elimination of welding assemblies23 as shown therein. The stem holder 79 includes upper and lower plates80 and 81 having a plurality of apertures 82 and 83, respectively, inaxially aligned fashion therein for receiving the pins 18 of stem 19. Arecess 84 is provided in the lower plate 81 for receiving a wheel-liketerminal engaging member 85. The engaging member 85 includes an outerrim 86 of insulating material secured to a centrally disposed hollowshaft 87 by a plurality of flexible conducting arms 88 equal in numberto the number of apertures 83 and each of which is normally disposed toone side of an associated aperture.

When assembled, the shaft 87 is securely fixed against rotation withinone or both of the upper and lower plates 80 and 81 and the latter aresecured together by means such as screws 89, the rim 86 of the engagingmember 85 protruding from the front of the assembled plates 80 and 81.Shaft 87 is formed of conducting material and provides a terminal towhich a welding potential is applied for connection to the flexibleconducting arms 88.

When inserting a stem 19, such as that shown in FIGS. 1 and 2, into thestem holder 79 of FIG. 3, the operator rotates the engaging member 85 byapplying a force in counterclockwise direction to the rim 86 thereof,causing the flexible conducting arms 88 to pass across and to theopposite side of the apertures 83. The pin members 18 of a stem member19 are then inserted through the apertures 83 of the lower plate 81 andinto the apertures 82 of the upper plate 80 and the engaging member 85is released. The resiliency of the flexible conducting arms 88 rotatesthe engaging member 85 in a clockwise direction, causing each of theflexible conducting arms 88 to engage the pin 18 extending through theaperture 83 adjacent thereto. The engagement of the flexible conductingarms 88 with the pins 18 serves both to retain the stem 19 within thestem holder 79 and to provide electrical connection through each of thepins 18 to the stem-leads 60. Thus, the conducting arm portions of theapparatus which are at the welding potential are completely enclosed,protecting the operator from accidentally touching such portions andbeing harmed thereby.

In FIG. 4 there is shown a simplified variety of an electron dischargedevice commonly known as a high voltage rectifier. There is againemployed a stem 19' having a plurality of pins 18' positioned in apredetermined array thereon, the pins 18 communicating, through theinsulating base member 61' of stem 19', with an associated plurality ofstem-leads 60'. The stem 19' further includes a tubulation portion 89formed thereon during manufacture of the stem 19' to facilitate handlingthereof during the assembly operation and also to provide an evacuatingoutlet tube for exhausting the completed electron discharge device. Thetubulation 89 is not shown in FIGS. 1 and 2 for purposes of each ofillustration.

Rather than the complex cage structure 63 of FIG. 2, the device of FIG.4 employs a discharge plate 90* of circular configuration to whichselected ones of the stemleads 60' are connected. An aperture 91 isprovided in the discharge plate 90 and a first wire-type electrode 92extends therethrough, the latter being secured, as by resistancewelding, to flap 93. A second electrode 94 extends through the aperture91, displaced from the discharge plate 90, and is connected to one ormore of the remaining stem-leads 60, these latter being bent tofacilitate the connection thereto.

Although the structure illustrated in FIG. 4 requires forming of thestem-leads 60" to provide the horizontally extending portions to whichthe second electrode 94 is welded, the time-consuming task of weldin theselected ones of the stem-leads 60 to the discharge plate 90 is avoidedby the percussive welding technique of the in vention, with consequentsavings in time and production expense. In a single operating step, thestem 19 is received within the stem holder 16 of FIGS. 1 and 2 and thedischarge plate 90, with or without the electrode 92 attached thereto,is positioned on a suitable support base similar to the support base 68of FIG. 2. The selected stem-leads 60' are then secured to the dischargeplate in accordance with the percussive welding technique hereinbeforeset out.

To derive even greater benefit from the teachings of this invention, thestem-leads 60 having the horizontally extending portions may be removed,leaving only the vertically-extending portions thereof, andinterconnecting bands (not shown) may be secured both to the shortened,vertically-extended portion of the stem-leads 60 and to thevertically-extending electrode 94 by percussive weldmg.

Additional modifications in the method of the inven tion and the use ofthe apparatus thereof will become apparent from the assemblies shown inFIGS. 5 and 6. In FIG. 5, a cage 95 is indicated including upper andlower insulating spacers or micas 96 and 97 having securely mountedtherebetween a plurality of electrode structures. The electrodes ofthese electrode structures provide a plurality of connector surfaces,the connector surfaces 98, 99, and 100 of the electrodes of electrodestructure 101 being selected for purposes of description. Aninterconnecting plate 102 is provided including a plurality ofinterconnecting bands, the bands 103, 104, and being selected forpurposes of discussion. Each of the bands 10.3-105 includes atransversely extending lip member 103a, 104a, and 105a, respectively,which is to be secured to the associated one of the electrode connectorsurfaces 98-100.

The transversely extending lip members 103a-105a are formed to beparallel to the direction in which the electrode connector surfaces,such as 99 and 100, extend Further, the interconnecting bands 104 and105 are designed to be of such a length that the operator may positionthe lip members 104a and 105a in contiguous relation to the connectorsurfaces. The operator then performs a plurality of successiveresistance welds to provide the completed assembly of FIG. 5.Illustratively, welding electrodes W and W are shown in disengagedpositions on opposite sides of lip member 105a and its associatedelectrode connector surface 100. Electrodes W and W are moved to aposition closely engaging the elements 105a and 100 and a current passedtherebetween to pro vide the resistance weld. Electrodes W and W arethen retracted, to the position shown, and the plurality of otherresistance welds are performed in an identical manner in a series ofsuccessive steps. Subsequently, a stem is welded to the interconnectingplate 102 in accordance with the percussive welding technique of theinvention in the manner indicated in FIGS. 1 and 2.

The completed structure is shown in FIG. 6, each of the stem-leads 60being joined to an associated one of the interconnecting bands ofinterconnecting plate 102 by a percussive weld. The interconnectingplate 102 and the cage 95 have been shown, in FIG. 6, rotated throughabout a vertical axis from the position shown in FIG. 5 to provide anadditional perspective for indicating the mannerof the formation of thelip members and the resistance and percussive welds. As a final step inthis assembly process, the peripheral portions 106 of theinterconnecting plate 102 are removed by breaking along the delineationsindicated by dotted lines in FIG. 6.

A further embodiment of the invention is indicated in FIG. 7 whereinthere is shown a cage 95' identical in form to the cage 95 shown in FIG.5 with the exception that-the upper mica 96 and the interconnectingplate 102 of FIG. 5 have been replaced by interconnecting bands formeddirectly on an upper support mica 107. The electrodes of the cage 95',such as those of the electrode structure 101', again include electrodeconnector surfaces extending through the upper mica 107. Theinterconnecting bands such as 103 to 105, are provided on the upper mica107 by printed circuit techniques. Further, the conducting surfaces ofthe interconnecting bands 103' to 105 may extend into, and in coatingrelation with, the interior walls defining the apertures in the uppermica 107 through which the electrode connector surfaces 94- 96,illustratively, extend to provide electrical connection therewith. Theconnector surfaces may be further secured in the apertures by a solderor conductive adhesive.

The assembly structure of FIG. 7, may then be positioned directly on asupporting base, such as the supportbase 68, in the apparatus of FIG. 2and a stem 19 secured thereto by the percussive welding technique of theinvention.

As clearly appears from the foregoing drawings and description of theinvention, the highly time consuming and very costly technique ofstem-lead forming, as required in the prior art may be totallyeliminated through the teachings of this invention. The utilization of apercussive welding technique, as taught by the invention, not onlyassures the rapid completion of a plurality of individual weldssimultaneously, it also avoids the use of resistance Welding electrodesand it can totally eliminate the costly, time-consuming step ofperforming individual resistance welds between each electrode connectorsurface and an associated stem-lead. One of the primary advantagesobtained in eliminating stem-lead forming is that the assembly operatorsare no longer required to become accustomed to each new electrodeconfiguration, and need not manipulate the device to perform a pluralityof resistance Welds. Upon a change-over in the production schedule, theassembly operator does not have to become acclimated to a new set oftwists and turns in a plurality of intermeshed, intricate stem-leads.

Many modifications and adaptations of the method and apparatus, and thestructure manufactured by the method and apparatus, of the invention'will readily be apparent to those skilled in the art. For example, thebringing of the parts together to perform the percussion welding neednot depend on the force of gravity but may be accomplished by springs orother more positive mechanical means. Thus, it will be understood thatthe terms, horizontal and vertical, are utilized to indicate theposition of parts relative to each other and not necessarily to indicatetheir specific position in space. Thus, it is intended by the appendedclaims to cover all such modifications and adaptations as fall withinthe true spirit and scope of the invention.

What I claim as new and desire to be secured by Letters Patent of theUnited States is:

1. In an electron discharge device,

(a) a stem formed of insulating material,

(b) a plurality of stem-leads of equal, predetermined length supportedin parallel, axial relation by said stem,

() a planar conducting element presenting a planar surface transverse tosaid stem-leads, and

(d) a percussive weld between the inner ends of selected ones of saidstem-leads and said planar conducting element.

2. In an electron discharge device,

(a) a stem formed of insultaing material,

(b) a plurality of stem-leads of equal, predetermined length supportedin parallel, axial relation by said stem,

(0) an electrode cage comprising electrode structures mounted on; aninsulating plate, said electrode structures including connector surfacesextending through said plate,

(d) an interconnecting plate comprising a planar sheet of conductingmaterial transverse to said stemleads formed to provide a plurality ofplanar interconnecting bands in insulated, spaced relation, each of saidinterconnecting bands interconnecting a selected one of said stem-leadsassociated therewith to an associated one of said electrode connectorsurfaces.

6. In an electron discharge diode rectifier,

' (a) a stem formed of insulating material,

(b) a plurality of stem-leads of equal, predetermined length supportedin parallel, axial relation by said stem,

(c) a plate of conducting material presenting a planar surfacetransverse to said stem-leads,

(d) an aperture in said plate,

(e) means for mounting a first electrode on said plate in mechanical andelectrical connection therewith,

(f) a percussive weld between the inner ends of selected ones of saidstem-leads and said plate, and

(g) means for mounting a second electrode by interconnection thereofWith a remaining one of said stem-leads to extend through said apertureand transverse to said plate.

4. In an electron discharge device including a stem formed of insulatingmaterial and an electrode cage comprising at least one insulatingsupport on which is mounted an electrode structure,

(a) electrode connector surfaces provided by each of the electrodes ofsaid electrode structure and extending through said insulating support,

(b) interconnecting bands of conducting material, each of saidinterconnecting bands providing electrical connection to an associatedone of said electrode connector surfaces,

(0) a plurality of stem-leads of equal, predetermined length supportedin parallel, axial relation by said stem,

(d) said interconnecting bands presenting a planar surface transverse tosaid stem-leads, and

(e) a percussive weld between the inner ends of selected ones of saidstem-leads and an associated one of said interconnecting bands.

5. An electron discharge device as recited in claim 4 wherein apercussive Weld is provided between said interconnecting bands and saidelectrode connector surfaces.

6. An electron discharge device as recited in claim 4 wherein saidinterconnecting bands include lip portions extending transverselythereto and disposed in parallel, axial relation contiguous to saidassociated electrode connector surfaces and wherein a resistance Weldjoins said lip portions to said surface.

7. In an electron discharge device including a stem formed of insulatingmaterial,

(a) an electrode cage comprising an insulating support on which ismounted an electrode structure, said insulating support having aplurality of apertures therein,

(b) said electrode structure including electrodes having electrodeconnector surfaces extending through said apertures of said insulatingsupport,

(0) a plurality of interconnecting bands of conducting material providedon said insulating support on the side thereof opposite from saidelectrode cage, said plurality of interconnecting bands being inmutually insulated, spaced relation, and each of said interconnectingbands providing electrical connection to an associated one of saidelectrode connector surfaces,

(d) a plurality of stem-leads of equal, predetermined length supportedin parallel, axial relation by said stem,

(e) said interconnecting bands presenting a planar surface transverse tosaid stem-leads, and

(f) a percussive weld between the inner ends of selected ones of saidstem-leads and associated ones of said interconnecting bands.

8. In an electron discharge device including a stem formed of insulatingmaterial and an electrode cage comprising an insulating support on whichis mounted an electrode structure.

(a) electrode connector surfaces provided by each of 13 the electrodesof said electrode structure and extending through said insulatingsupport,

(b) a plurality of stem-leads of equal, predetermined length supportedin parallel, axial relation by said stem and disposed in a fixed arraythereon,

(c) a plurality of interconnecting bands comprising generally planarstrips of conducting material positioned transverse to said stem-leads,

(d) each of said interconnecting bands extending between a firstposition corresponding to the position 10 of a selected one of saidstem-leads in said fixed array and a second position corresponding to anassociated one of said electrode connector surfaces to provideelectrical connection therebetween.

9. An electron discharge deviceas recited in claim 8 'wherein apercussive weld is provided between each of said interconnecting bandsand the inner end of a selected one of said stem-leads by a percussiveweld.

10. An electron discharge device as recited in claim 8 wherein apercussive weld is provided between each of 20 said interconnectingbands and an electrode connector surface associated therewith.

11. An electron discharge device as recited in claim 8 wherein each ofsaid interconnecting bands includes a lip portion extending transverselythereto and disposed in parallel, axial relation contiguous to saidelectrode connector surface associated therewith and wherein aresistance weld joins said lip portion to said surface.

References Cited UNITED STATES PATENTS 2,749,528 6/1956 Albrecht 21996 X2,882,387 4/1959 Rively et a1. 219-96 2,907,911 10/1959 Miller et a1.313--317 X 2,960,595 11/1960 Harhuis et a1. 219-107 2,985,806 5/1961McMahon et a1. 317-235 3,270,391 9/1966 Linehan 31 3317 X 3,365,6061/1966 Keating 313317 X 3,375,343 3/1968 Dupre 219-96 JOHN HUCKERT,Primary Examiner A. J. JAMES, Assistant Examiner US. Cl. X.R.

